The present invention relates to an anhydrous phenol treatment method for restoring deactivated sulfonated aromatic organic polymeric ion-exchange resin having chemically combined aminoorganomercaptan groups. More particularly, a method is provided for treating a deactivated ion exchange resin with anhydrous phenol at elevated temperatures to effect the reaction of phenol with deactivated aminoorganomercaptan groups and the simultaneous elution of phenolic reaction products from the ion-exchange resin.
As shown in copending application Ser. No. 08/236,816 a sulfonated aromatic organic polymeric ion-exchange resin bed having chemically combined aminoorganomercaptan groups can be used to catalyze the condensation of phenol and ketone, such as acetone. However, excessive exposure of such "thiol containing" ion-exchange resin to phenol contaminated with at least 1 ppm of hydroxyacetone can substantially reduce the effectiveness or "deactivate" the ion-exchange resin. It has been found that contact between the hydroxyacetone contaminant and aminoorganomercaptan groups can result in the formation of a chemically combined species. The species can substantially interfere with the ability of the ion-exchange resin to perform effectively as a condensation catalyst for making bisphenol.
Another application of the thiol containing ion exchange resin taught in copending application Ser. No. 08/236,816 is as a sacrificial ion-exchange resin guard bed having chemically combined aminoorganomercaptan groups. The ion-exchange resin guard bed can be used to provide a purified phenol effluent substantially free of hydroxyacetone which can extend the life of the ion-exchange resin condensation reactor bed.